Venezia R A, Ryan A, Alward S, Kostun W A
J Clin Microbiol. 1985 Mar;21(3):395-8. doi: 10.1128/jcm.21.3.395-398.1985.
Throat swabs from 196 pediatric patients were processed by a direct extraction-latex agglutination method (Group A Strep Direct Antigen Identification Test [DAI]) that detects group A streptococci in the specimen. The method requires a 45-min enzymatic extraction period at 37 degrees C and a 4-min reaction period with antibody-linked latex particles. The results were compared with those of the culture and fluorescent antibody methods and the clinical presentation of the patient for pharyngitis. Ninety-three percent of the specimens resulted in agreement by all tests, and 28% were culture positive for group A streptococci. Compared with the culture method, the DAI had a sensitivity and a specificity of 83% and 99%, respectively. The positive predictive values were 98% versus the culture method and 93% versus the fluorescent antibody method, whereas the negative predictive values were 94% versus both other methods. Of the 14 discrepant results when both clinical presentation of an acute pharyngitis and the test results were compared, the culture method provided the best correlation. An additional 64 specimens were processed by the DAI and another direct extraction-latex agglutination method (Culturette Ten-Minute Group A Strep ID Test), and the results were compared with those of the culture method. This group had a 40.6% culture isolation rate for group A streptococci. The sensitivity and specificity of the DAI and Strep ID methods versus the culture method were 81 and 100%, and 77 and 97%, respectively. These results indicate that the DAI is accurate for diagnosing group A streptococcal pharyngitis directly from throat swabs. However, negative results in the presence of a symptomatic patient must be confirmed by standard culture techniques.
采用直接提取 - 乳胶凝集法（A 组链球菌直接抗原鉴定试验[DAI]）对196例儿科患者的咽拭子进行处理，该方法可检测标本中的 A 组链球菌。该方法需要在37摄氏度下进行45分钟的酶提取期，并与抗体连接的乳胶颗粒进行4分钟的反应期。将结果与培养法和荧光抗体法的结果以及患者咽炎的临床表现进行比较。所有检测结果中93%一致，28%的标本 A 组链球菌培养呈阳性。与培养法相比，DAI 的敏感性和特异性分别为83%和99%。与培养法相比，阳性预测值为98%，与荧光抗体法相比为93%，而与其他两种方法相比，阴性预测值均为94%。在比较急性咽炎的临床表现和检测结果时出现的14个不一致结果中，培养法提供了最佳相关性。另外64份标本采用 DAI 和另一种直接提取 - 乳胶凝集法（Culturette 十分钟 A 组链球菌鉴定试验）进行处理，并将结果与培养法的结果进行比较。该组 A 组链球菌的培养分离率为40.6%。与培养法相比，DAI 和链球菌鉴定法的敏感性和特异性分别为81%和100%，以及77%和97%。这些结果表明，DAI 可直接从咽拭子准确诊断 A 组链球菌性咽炎。然而，有症状患者检测结果为阴性时，必须通过标准培养技术进行确认。
